I shoot both the 270 and 308 and have taken deer with both. The 270, 280, 7mm08, 308, 30-06 will all do the job. They have similar ballistics, with relatively minor differences. My favorite is the 308 for the short action and the fact that you can use some heavier bullets if you need to. Plus I find it a little easier to shoot off the bench. If you already have a gun in any of these calibers that you are comfortable with there is no real gain in switching. The short fat case of the 308 has proven more accurate, but most hunters aren't shooting in 600 yd matches where it really makes a difference. I use 150 grain psp's for eastern whitetails. For long range shooting on mule deer I would use a 165gr Swift Scirrocco if accurate in your gun. For Elk or Moose a 180 gr. premium partition.

I would use the 308 on anything in North America except the grizzly. I would use a 338 winmag for them.

Good luck and happy hunting!